The present invention relates to a system and method for measuring an air flow rate. More specifically, the invention relates to a system and method for measuring an air flow rate suitable for application in an intake air flow measuring device of an automotive internal combustion engine.
In an automotive engine, it is a trend to employ an electronic control system for primarily controlling a fuel flow rate and/or a spark ignition timing with high precision and high accuracy employing a microcomputer in order to satisfy requirements for protection of the environment and for improvement of fuel economy. In such electronic control system, a plurality of sensors and actuators are required for obtaining information from the engine. Particularly, an air flow measuring device for an intake air introduced into the engine and an air temperature measuring device for an air introduced into the engine are essential for controlling a fuel injection amount and the spark ignition timing.
As an example of a measuring system from the background set forth above, having an air temperature measuring function in addition to production of an air flow indicative signal, utilizing an air flow measuring device, has been disclosed in Japanese Examined Patent Publication No. 1-100423. In this example, only method for obtaining the signals have been discussed and no disclosure is provided for transmission of the detection signals.
In order to achieve improvement of fuel economy of an automotive vehicle, it is important to reduce a weight of the vehicle per se together with precise control by the electronic control.